NEBOSH National Diploma cheat sheet

Hierarchy of control (legal order, England/Wales): eliminate, substitute, engineering controls, administrative controls, PPE - PPE is the last resort and never a substitute for elimination.

Risk = likelihood × severity of harm; residual risk is the risk remaining after controls, and must be judged against a defined tolerable/acceptable threshold, not assumed to be zero.

ALARP (as low as reasonably practicable): cost of further risk reduction must be grossly disproportionate to the benefit before stopping; the higher the hazard, the greater the sacrifice expected.

Reasonably practicable is narrower than physically possible: it weighs risk against time, trouble and cost, whereas 'practicable' weighs only technical feasibility.

Accident ratio models (e.g. Bird's triangle) illustrate that many minor incidents precede serious ones, so near-miss reporting is a leading indicator, not a lagging one.

Swiss-cheese model: accidents occur when holes in multiple defensive layers align; layers include engineered controls, administrative controls and human behaviour.

Duty-holder mapping: employer duties are non-delegable; employees have duties to cooperate and report; designers, manufacturers and suppliers carry duties for articles/substances for use at work.

Competence = sufficient training, experience and knowledge for the task; supervision level should be set by risk, competence and task complexity, not by seniority alone.

Five steps of risk assessment: identify hazards; decide who may be harmed and how; evaluate risks and decide controls; record significant findings; review and update.

Suitable and sufficient risk assessment must identify hazards, ignore trivial risks, consider all affected persons including non-employees, and be proportionate to the risk.

Hierarchy for choosing controls in practice: apply the highest-level control that is reasonably practicable, then add lower-level controls only to cover residual risk.

Accident investigation aims to establish root and underlying causes (management system failures), not just immediate causes; recommendations must be SMART and tracked to closure.

Immediate causes are unsafe acts and unsafe conditions; underlying causes include poor supervision, inadequate training, and missing procedures; root causes are failures in the management system.

POPMAR (policy, organising, planning and implementing, measuring performance, audit and review) maps to the elements of a health and safety management system.

Active (proactive) monitoring measures compliance and control before harm, e.g. inspections, audits, safety sampling; reactive monitoring measures failures, e.g. incidents, sickness absence, enforcement notices.

Performance standards should be measurable and assigned to a named responsible person with a completion date, so audit can verify implementation objectively.

Occupational exposure limits: WELs are set for airborne substances; the long-term limit is a 15-minute reference period and the short-term limit is a 15-minute reference period, with the long-term 8-hour TWA used for chronic exposure.

COSHH assessment is required before work with a hazardous substance; control is by elimination/substitution first, then engineering controls, then safe systems of work and PPE.

Noise: lower exposure action value 80 dB(A) daily/ weekly; upper exposure action value 85 dB(A); exposure limit value 87 dB(A) - the limit value must not be exceeded even with hearing protection.

Hand-arm vibration: action value 2.5 m/s² A(8); limit value 5 m/s² A(8); exposure duration and tool vibration magnitude determine the A(8) value.

Manual handling risk assessment considers task, load, individual capability, environment and other factors; the kinetic method or MAC/RAPP tools support structured evaluation.

Human error types: slips (attention failure), lapses (memory failure), mistakes (rule-based or knowledge-based error) and violations (deliberate deviation); each needs different controls.

Display screen equipment: DSE assessment covers workstation, equipment, environment and task; users are entitled to eye tests and breaks from screen work.

Stress management (HSE Management Standards) covers demands, control, support, relationships, role and change; assess against these six areas to target interventions.

Criminal law imposes duties on employers; breach of a statutory duty is enforced by the regulator, and penalties range from improvement/prohibition notices to unlimited fines and imprisonment for individuals.

Civil law allows an injured person to claim damages; the employer owes a duty of reasonable care, and vicarious liability can make the employer liable for employees' acts in the course of employment.

Improvement notice: requires remedy of a contravention within a stated period; prohibition notice: stops an activity that involves a risk of serious personal injury, with immediate or deferred effect.

Enforcement options: informal action, improvement notice, prohibition notice, prosecution, and withdrawal of approvals; the regulator must apply the enforcement policy and consider the enforcement management model.

RIDDOR reporting: deaths, specified injuries, over-7-day injuries, dangerous occurrences and occupational diseases must be reported to the enforcing authority within set timescales.

Corporate manslaughter requires a gross breach of a relevant duty of care causing death, with the breach attributable to the organisation's senior management.

Sentencing guidelines for health and safety offences consider culpability (negligent to deliberate), harm category, turnover and aggravating/mitigating factors.

Emergency planning: identify foreseeable emergencies, establish alarm and evacuation arrangements, appoint competent persons, practise drills and review after every exercise or incident.

Audit vs inspection: audit is a systematic, independent, documented evaluation of the management system; inspection is a physical check of conditions and behaviour against standards.

Audit types include internal (first-party), external (second-party supplier, third-party certification) and compliance audits; independence and competence of auditors are essential.

Audit process: scope and criteria, planning, evidence gathering, findings, report, corrective action and follow-up; findings are classified as conformities, observations or nonconformities.

Key performance indicators should be leading (training completion, inspection closure rate) or lagging (incident rates, lost-time injury frequency rate) and be trended over time.

Accident incidence rate = (number of accidents × 1,000) / average number of workers; accident frequency rate = (number of accidents × 1,000,000) / hours worked.

Accident severity rate = (days lost × 1,000) / hours worked; these rates allow comparison between sites and over periods, but must use consistent definitions.

Continual improvement cycle (Plan–Do–Check–Act) applies to health and safety management systems; review should feed back into policy, objectives and risk assessment.

Safety culture maturity moves from pathological (blame) through reactive and calculative to proactive and generative; indicators include reporting rates and management commitment.